Known from U.S. Pat. No. 4,987,668 is a generic machine tool wherein the tool carrier is vertically placed on a machine support and wherein the horizontally lodged spindle can be moved in the x and y-direction. The work piece holder is also placed on the machine support and can be displaced in z-direction and be turned around a vertical axis, too. Mobility of the work spindle in z-direction is not feasible and/or not provided for therein.
EP-0 232 548 A2 describes a processing station, particularly for comparably large work pieces, equipped with a processing unit preferably having a laser, wherein the processing unit is also lodged at a frame-like vertical support post and can be moved in x-, y-, and z-direction,
On certain applications, e.g. on high-speed and/or high-precision processing, it became evident that high acceleration and processing forces act on the tool carrier when the processing unit is moved in z-direction. On processing it might lead to inaccuracies, and it calls for a very stable and expensive design and construction of the tool carrier, particularly if the work space is very large and if the feed forward speed and/or acceleration rate are very fast. Moreover, substantial displacement between tool side and work piece side has frequently become evident in processing centers known thus far, due to involvement of coolants, different coolant temperatures, and changes in hall temperature.
Known from DE 38 32 975 C1 is a multiple-spindle autolathe with a frame-like casing consisting of a bottom machine bed, a spindle post with a controllable spindle drum, a drive post for the drives of the processing tools and a top traverse between spindle post and drive post. The work space is interspersed by a central pipe on which a longitudinal slide block is placed and which rests supported in the spindle drum on the one hand and in the drive post on the other hand.
Mobility of the spindle by the aid of x-, y-, and z-slides is not provided for hereunder. Moreover only relatively small work pieces can be processed.